using System; 
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data.Linq.Mapping;
using System.Data.Linq.Provider; 
using System.Linq.Expressions;
using System.Diagnostics.CodeAnalysis; 
 
namespace System.Data.Linq.SqlClient {
 
    internal enum SqlParameterType {
        Value,
        UserArgument,
        PreviousResult 
    }
 
    internal class SqlParameterInfo { 
        SqlParameter parameter;
        object value; 
        Delegate accessor;
        internal SqlParameterInfo(SqlParameter parameter, Delegate accessor) {
            this.parameter = parameter;
            this.accessor = accessor; 
        }
        internal SqlParameterInfo(SqlParameter parameter, object value) { 
            this.parameter = parameter; 
            this.value = value;
        } 
        internal SqlParameterInfo(SqlParameter parameter) {
            this.parameter = parameter;
        }
        internal SqlParameterType Type { 
            get {
                if (this.accessor != null) { 
                    return SqlParameterType.UserArgument; 
                }
                else if (this.parameter.Name == "@ROWCOUNT") { 
                    return SqlParameterType.PreviousResult;
                }
                else {
                    return SqlParameterType.Value; 
                }
            } 
        } 
        internal SqlParameter Parameter {
            get { return this.parameter; } 
        }
        internal Delegate Accessor {
            get { return this.accessor; }
        } 
        internal object Value {
            get { return this.value; } 
        } 
    }
 
    internal class SqlParameterizer {
        TypeSystemProvider typeProvider;
        SqlNodeAnnotations annotations;
        int index; 

        internal SqlParameterizer(TypeSystemProvider typeProvider, SqlNodeAnnotations annotations) { 
            this.typeProvider = typeProvider; 
            this.annotations = annotations;
        } 

        internal ReadOnlyCollection<SqlParameterInfo> Parameterize(SqlNode node) {
            return this.ParameterizeInternal(node).AsReadOnly();
        } 

        private List<SqlParameterInfo> ParameterizeInternal(SqlNode node) { 
            Visitor v = new Visitor(this); 
            v.Visit(node);
            return new List<SqlParameterInfo>(v.currentParams); 
        }

        internal ReadOnlyCollection<ReadOnlyCollection<SqlParameterInfo>> ParameterizeBlock(SqlBlock block) {
            SqlParameterInfo rowStatus = 
                new SqlParameterInfo(
                    new SqlParameter(typeof(int), typeProvider.From(typeof(int)), "@ROWCOUNT", block.SourceExpression) 
                    ); 
            List<ReadOnlyCollection<SqlParameterInfo>> list = new List<ReadOnlyCollection<SqlParameterInfo>>();
            for (int i = 0, n = block.Statements.Count; i < n; i++) { 
                SqlNode statement = block.Statements[i];
                List<SqlParameterInfo> parameters = this.ParameterizeInternal(statement);
                if (i > 0) {
                    parameters.Add(rowStatus); 
                }
                list.Add(parameters.AsReadOnly()); 
            } 
            return list.AsReadOnly();
        } 

        internal virtual string CreateParameterName() {
            return "@p" + this.index++;
        } 

        class Visitor : SqlVisitor { 
            private SqlParameterizer parameterizer; 
            internal Dictionary<object, SqlParameterInfo> map;
            internal List<SqlParameterInfo> currentParams; 
            private bool topLevel;
            private ProviderType timeProviderType;  // for special case handling of DateTime parameters

            internal Visitor(SqlParameterizer parameterizer) { 
                this.parameterizer = parameterizer;
                this.topLevel = true; 
                this.map = new Dictionary<object, SqlParameterInfo>(); 
                this.currentParams = new List<SqlParameterInfo>();
            } 

            private SqlParameter InsertLookup(SqlValue cp) {
                SqlParameterInfo pi = null;
                if (!this.map.TryGetValue(cp, out pi)) { 
                    SqlParameter p;
                    if (this.timeProviderType == null) { 
                        p = new SqlParameter(cp.ClrType, cp.SqlType, this.parameterizer.CreateParameterName(), cp.SourceExpression); 
                        pi = new SqlParameterInfo(p, cp.Value);
                    } 
                    else {
                        p = new SqlParameter(cp.ClrType, this.timeProviderType, this.parameterizer.CreateParameterName(), cp.SourceExpression);
                        pi = new SqlParameterInfo(p, ((DateTime)cp.Value).TimeOfDay);
                    } 
                    this.map.Add(cp, pi);
                    this.currentParams.Add(pi); 
                } 
                return pi.Parameter;
            } 

            internal override SqlExpression VisitBinaryOperator(SqlBinary bo)
            {
                // 
                // Special case to allow DateTime CLR type to be passed as a paramater where
                // a SQL type TIME is expected. We do this only for the equality/inequality 
                // comparisons. 
                //
                switch (bo.NodeType) { 
                    case SqlNodeType.EQ:
                    case SqlNodeType.EQ2V:
                    case SqlNodeType.NE:
                    case SqlNodeType.NE2V: { 
                        SqlDbType leftSqlDbType = ((SqlTypeSystem.SqlType)(bo.Left.SqlType)).SqlDbType;
                        SqlDbType rightSqlDbType = ((SqlTypeSystem.SqlType)(bo.Right.SqlType)).SqlDbType; 
                        if (leftSqlDbType == rightSqlDbType) 
                            break;
 
                        bool isLeftColRef = bo.Left is SqlColumnRef;
                        bool isRightColRef = bo.Right is SqlColumnRef;
                        if (isLeftColRef == isRightColRef)
                            break; 

                        if (isLeftColRef && leftSqlDbType == SqlDbType.Time && bo.Right.ClrType == typeof(DateTime)) 
                            this.timeProviderType = bo.Left.SqlType; 
                        else if (isRightColRef && rightSqlDbType == SqlDbType.Time && bo.Left.ClrType == typeof(DateTime))
                            this.timeProviderType = bo.Left.SqlType; 
                        break;
                    }
                }
                base.VisitBinaryOperator(bo); 
                return bo;
            } 
 
            internal override SqlSelect VisitSelect(SqlSelect select) {
                bool saveTop = this.topLevel; 
                this.topLevel = false;
                select = this.VisitSelectCore(select);
                this.topLevel = saveTop;
                select.Selection = this.VisitExpression(select.Selection); 
                return select;
            } 
 
            internal override SqlUserQuery VisitUserQuery(SqlUserQuery suq) {
                bool saveTop = this.topLevel; 
                this.topLevel = false;
                for (int i = 0, n = suq.Arguments.Count; i < n; i++) {
                    suq.Arguments[i] = this.VisitParameter(suq.Arguments[i]);
                } 
                this.topLevel = saveTop;
                suq.Projection = this.VisitExpression(suq.Projection); 
                return suq; 
            }
 
            [SuppressMessage("Microsoft.Design", "CA1061:DoNotHideBaseClassMethods", Justification="Unknown reason.")]
            internal SqlExpression VisitParameter(SqlExpression expr) {
                SqlExpression result = this.VisitExpression(expr);
                switch (result.NodeType) { 
                    case SqlNodeType.Parameter:
                        return (SqlParameter)result; 
                    case SqlNodeType.Value: 
                        // force even literal values to become parameters
                        return this.InsertLookup((SqlValue)result); 
                    default:
                        System.Diagnostics.Debug.Assert(false);
                        return result;
                } 
            }
 
            internal override SqlStoredProcedureCall VisitStoredProcedureCall(SqlStoredProcedureCall spc) { 
                this.VisitUserQuery(spc);
 
                for (int i = 0, n = spc.Function.Parameters.Count; i < n; i++) {
                    MetaParameter mp = spc.Function.Parameters[i];
                    SqlParameter arg = spc.Arguments[i] as SqlParameter;
                    if (arg != null) { 
                        arg.Direction = this.GetParameterDirection(mp);
                        if (arg.Direction == ParameterDirection.InputOutput || 
                            arg.Direction == ParameterDirection.Output) { 
                            // Text, NText and Image parameters cannot be used as output parameters
                            // so we retype them if necessary. 
                            RetypeOutParameter(arg);
                        }
                    }
                } 

                // add default return value 
                SqlParameter p = new SqlParameter(typeof(int?), this.parameterizer.typeProvider.From(typeof(int)), "@RETURN_VALUE", spc.SourceExpression); 
                p.Direction = System.Data.ParameterDirection.Output;
                this.currentParams.Add(new SqlParameterInfo(p)); 

                return spc;
            }
 
            private bool RetypeOutParameter(SqlParameter node) {
                if (!node.SqlType.IsLargeType) { 
                    return false; 
                }
                ProviderType newType = this.parameterizer.typeProvider.GetBestLargeType(node.SqlType); 
                if (node.SqlType != newType) {
                    node.SetSqlType(newType);
                    return true;
                } 
                // Since we are dealing with a long out parameter that hasn't been
                // retyped, we need to annotate 
                this.parameterizer.annotations.Add( 
                    node,
                    new SqlServerCompatibilityAnnotation(
                        string.Format(Strings.MaxSizeNotSupported,node.SourceExpression), SqlProvider.ProviderMode.Sql2000));
                return false;
            }
 
            [SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification="Unknown reason.")]
            private System.Data.ParameterDirection GetParameterDirection(MetaParameter p) { 
                if (p.Parameter.IsRetval) { 
                    return System.Data.ParameterDirection.ReturnValue;
                } 
                else if (p.Parameter.IsOut) {
                    return System.Data.ParameterDirection.Output;
                }
                else if (p.Parameter.ParameterType.IsByRef) { 
                    return System.Data.ParameterDirection.InputOutput;
                } 
                else { 
                    return System.Data.ParameterDirection.Input;
                } 
            }

            internal override SqlStatement VisitInsert(SqlInsert sin) {
                bool saveTop = this.topLevel; 
                this.topLevel = false;
                base.VisitInsert(sin); 
                this.topLevel = saveTop; 
                return sin;
            } 

            internal override SqlStatement VisitUpdate(SqlUpdate sup) {
                bool saveTop = this.topLevel;
                this.topLevel = false; 
                base.VisitUpdate(sup);
                this.topLevel = saveTop; 
                return sup; 
            }
 
            internal override SqlStatement VisitDelete(SqlDelete sd) {
                bool saveTop = this.topLevel;
                this.topLevel = false;
                base.VisitDelete(sd); 
                this.topLevel = saveTop;
                return sd; 
            } 

            internal override SqlExpression VisitValue(SqlValue value) { 
                if (this.topLevel || !value.IsClientSpecified || !value.SqlType.CanBeParameter) {
                    return value;
                }
                else { 
                    return this.InsertLookup(value);
                } 
            } 

            internal override SqlExpression VisitClientParameter(SqlClientParameter cp) { 
                if (cp.SqlType.CanBeParameter) {
                    SqlParameter p = new SqlParameter(cp.ClrType, cp.SqlType, this.parameterizer.CreateParameterName(), cp.SourceExpression);
                    this.currentParams.Add(new SqlParameterInfo(p, cp.Accessor.Compile()));
                    return p; 
                }
                else { 
                    return cp; 
                }
            } 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.